1. Field of Invention
The present invention relates to a signal manipulator, and more particularly, to a knob assembly for controlling signal output through rotational or linear movement.
2. Related Art
A human-computer interface serves as a communication interface between an electronic product and a user, and the user instructs the electronic product to execute corresponding default commands through manipulating the human-computer interface. Portable electronic devices such as notebook computers, PDAs, or mobile phones, have various kinds of human-computer interfaces in various shapes, for example, mechanical pressing keys or touch buttons. The user can make a command of “Select”, “Execute”, or “Terminate”, through pressing or touching the human-computer interfaces, such that the portable electronic device performs corresponding actions according to the user's command.
As for the human-computer interface, with reference to US Patent Publication U.S. Pat. No. 6,396,419 (hereinafter Case 419 for short), it discloses a digital volume control knob for a laptop computer, and mentions that, a conventional laptop computer uses an audiovisual software, a variable resistor, or a hot key to control the volume. However, the aforementioned methods have the disadvantage that it is difficult to control, or it is easy to cause malfunction, and thus Case 419 discloses a digital volume control knob using a variable resistor as the switch to control the volume.
As shown in FIG. 1, the digital volume control knob includes a primary control device 14 and a secondary control device 16, wherein the primary control device 14 further includes a control panel 141 and a blade spring, and the secondary control device 16 further includes a plurality of chips 162. The control panel 141 is operated by the user to rotate or move linearly, and when the user operates the control panel 141, the blade spring is made to touch the chips 162 in different positions. That is, each corresponding default signal (such as a signal for controlling the volume) may be outputted, so as to play a corresponding large or small sound or be mute.
In the volume control knob disclosed in Case 419, the chip 162 disposed on the secondary control device 16 is a conductive metal sheet that forms a contacting region, such that the blade spring of the control panel 141 contacts and then electrically communicates with the conductive metal sheet to output the default signals. When the blade spring of the control panel 141 is still in the contacting region, the signals are continuously outputted (for example, the volume continuously becomes larger or smaller). When another pressure is applied to force the blade spring of the control panel 141 to release from the contacting region of the chip 162, the signal is switched off.
Case 419 solves the problems of the software control, the variable resistor control, or the hot key control. However, the chip 162 forming the electrical connection is a contacting region, and thus, when the signal is switched off and an external force is applied to the control panel 141, a time difference still exists from applying the external force to releasing the blade spring from the contacting area of the chip 162. That is, the user has adjusted to the desired volume and then released the control panel 141, and at this time, the blade spring is still not released from the chip 162 yet. As such, a difference occurs between the expected value of the user and the actual value.